First of all, a ranging procedure according to a related art is described with reference to FIG. 1. FIG. 1 is a diagram for a ranging procedure according to a related art.
A terminal performs a ranging procedure in case of attempting an initial access or making a handover. Referring to FIG. 1, a terminal transmits a ranging code to a base station [S110]. Having received the ranging code, the base station allocates an uplink (UL) resource by transmitting a CDMA allocation IE (information element) to the terminal via an uplink-MPA (hereinafter abbreviated UL-MAP) viewable to all terminals [S120].
The terminal sends a ranging request (hereinafter abbreviated RNG-REQ) message via an allocated UL resource region [S130]. In case that the terminal performs a ranging procedure for an initial access, the terminal delivers the RNG-REQ message with a connection ID (hereinafter abbreviated CID) for the initial ranging.
Having received the RNG-REQ message, the base station allocates a DL resource to carry a ranging response (hereinafter abbreviated RNG-RSP) message via a downlink-MAP (hereinafter abbreviated DL-MAP) viewable to all terminals [S140]. The base station then delivers the RNG-RSP message via the allocated DL resource [S150]. In case that the terminal performs a ranging procedure for an initial access, the base station delivers the RNG-RSP message for the initial ranging.
Regarding a bandwidth request procedure according to a related art, if a terminal transmits a bandwidth request (BR) code too a base station, the base station allocates a UL resource via CDMA allocation UL-MAP IE. If so, the terminal sends a bandwidth request message via the allocated UL resource. Having received the bandwidth request message, the base station allocates a UL resource to the terminal. The terminal then transmits data via the allocated UL resource.
In particular, in a ranging procedure and a bandwidth request procedure, a terminal transmits a code to a base station. Having received the code, the base station allocates a UL resource via CDMA allocation UL-MAP IE.
Table 1 shows a format of CDMA allocation UL-MAP IE according to a related art.
TABLE 1SizeSyntax(bit)NotesCDMA_Allocation_IE( ) {—— Duration6— UTUC4UTUC for transmission Repetition Coding20b00: No repetition coding Indication0b01: Repetition coding of 2 used0b10: Repetition coding of 4 used0b11: Repetition coding of 6 used Frame Number Index4LSBs of relevant frame number Ranging Code8— Ranging Symbol8— Ranging subchannel7— BW request mandatory11: Yes0: No}——
According to a related art, each of all terminal having attempted the ranging checks RNG-RSP message and may be then able to aware whether the corresponding message has been sent to the corresponding terminal.
A terminal checks whether RNG-RSP message has been set to itself through an index of a ranging code contained in the RNG-RSP message and information on a timing point of transmitting the ranging code. Subsequently, the terminal ignores the RNG-RSP message if the RNG-message is not sent to the corresponding terminal.
Thus, the related art has a problem that the corresponding terminal should decode the RNG-RSP message unnecessarily.
In 802.16m system, a bandwidth request channel and a ranging are designed in different forms, respectively. Hence, a case for a base station to receive a ranging code differs from a case for the base station to receive a bandwidth request code in information supposed to be sent to a terminal.
Therefore, CDMA allocation IE in 802.16m system needs to contain proper information and also needs to be designed to be suitable for a basic A-MAP IE form of the 802.16m system.